Embryology Flashcards
Where is the egg fertilized
The ampulla of the fallopian tube
What is considered the first fate decision for cells in the blastocyst formation
And when does it take place
ICM cells that will become the embryo or Trophoblast (outside cells that will form part of the placenta)
Begins with the compaction of blastomeres at the 8 cell stage
What is considered the 2nd fate steps for the developing embryo
ICM cells either becoming the epiblast or hypoblast
What is the epiblast going to become
Amnion and body of the embryo
What is the fate of the hypoblast
It will form the wall of the primitive and secondary yolk sacs
When does the primitive streak form, where does it form, and what is the significance of this
Early in the 3 week, begins in the caudal half of the disc. Epiblast cells migrate laterally and anteriorly through the primitively streak
What are the 3 germ layers
Ectoderm
Mesoderm
Endoderm
What is the primitive node/notochord
The primitively node is the anterior end of the primitively streak and the notochord is mesodermal cells forming a solid chord in the midline
What will the notochord become
It will become the nucleus pulposus of the vertebral discs as well as induce ectoderm to become nervous tissue
Sacrococcygeal teratoma
Remnant of the primitive streak that is a benign tumor containing tissues of all 3 germ layers
What is is the oral pharyngeal membrane and what does it consist of
Future side of the oral cavity and only ectoderm and endoderm
Prechordal plate contributes to what
Forebrain and the oral cavity
What is the cloacal membrane
Site of the future anus and is only the ectoderm and endoderm
What does the ectoderm become
Nervous tissue (CNS/PNS)
Neural crest cells(ganglia,adrenal medial, melanocytes)
Skin(from surface ectoderm, glands)
When is the neural plate formed and what does it do.
It is the ecotoderm above the notochord forming the neural ectoderm. Periphery cells fold the neural ectoderm into a tube. Surface ectoderm covers the neural tube and becomes the epidermis
When does the neruo tube close
4 weeks (28) days
Neural tube defects
Preventative measures
Failure to close the neural tube at the cranial end causes ancephally
Failure to close the neural tube from the caudal end causes spina bifida
Folic acid
What do the neural crest cells become
Ganglion of all types
What layers forms the somites
Mesoderm
What does the paraxial mesoderm become
Somites and axial skeleton, associated muscle, and the dermis of the skin
What do cells front he somites form
The dermis, muscle, and tendons, cartilage, and bone
What does the intermediate mesoderm form
Urogenital structures
Where do germ cells arise and where do they migrate to
From the epiblast and migrate to genital ridge
Lateral plate mesoderm somatic and visceral layer fates
Somatic=body wall, bones and CT
Visceral=cover organs
What composes the body wall when the embryonic disc folds laterally
Parietal mesoderm and ectoderm
What forms the gut wall when he embryonic disc folds laterally
Endoderm and the visceral mesoderm
Where do blood islands first form
In the mesoderm of the wall of the yolk sac
Vasculogenesis
Blood vessels derived from blood islands
Angiogenesis
Sprouting of vessels from existing vessels
Where does the heart sprout from
The mesoderm of the cardiogenic area. And as the neural tube grows/folding of the cranial region, the heart is directed to the thoracic region
What does the endoderm differentiate into
Epithelial lining of the GI, lung, thyroid, liver, pancreas
When does the fetal period begin
The 3rd month
